Night Mode (warmer temperatures)

[CptFoobar]

This feature has been on my mind for quite some time, and has also been requested by a few users. If you are familiar with the application f.lux, you'll know what I'm talking about. If not, you may want to check that link out. The idea is to increase the temperatures of colors at night for a more comfortable experience. I personally have found the warmer colors very helpful in reducing strain on eyes during night-long coding sessions, and would like to offer a similar functionality to Owl users. You can read the research behind this here. As for the code, I can see this implemented as an additional CSS that is applied on top of the chosen Owl theme. I have two ideas on the method of choosing the temperature. One would be to allow a slider in settings page of the add-on for the user to select the precise temperature they want. However this would require dynamically generating a CSS that fits that temperature settings, and might be a bit more work. The other can providing the user with 5-7 predefined temperature settings, and have predefined CSS for each. The mode would be activated/deactivated as per the times set by the user.